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Study Title and Description

Effects of encapsulated green tea and Guarana extracts containing a mixture of epigallocatechin-3-gallate and caffeine on 24 h energy expenditure and fat oxidation in men.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
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Primary Publication Information
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TitleData
Title Effects of encapsulated green tea and Guarana extracts containing a mixture of epigallocatechin-3-gallate and caffeine on 24 h energy expenditure and fat oxidation in men.
Author S Bérubé-Parent,C Pelletier,J Doré,A Tremblay,
Country
Year 2005
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
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What is the objective of the study (as reported by the authors)? The first aim of the present study was to assess the impact of four mixtures of green tea and Guarana (a plant that contains caffeine) extracts containing a fixed 600 mg daily dose of caffeine and different amounts of epigallocatechin-3-gallate (EGCG) (270 mg/d; 600 mg/d; 900 mg/d; 1200 mg/d) on 24 h energy expenditure, RQ and substrate oxidation in comparison with a placebo.
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) Subjects Healthy, non-smoking and sedentary men (n = 14), from 20 to 50 years of age and with BMI between 20 and 27 kg/m2, were selected to participate in the study. Subjects on a particular diet (vegetarian), subjects consuming a diet rich in capsaicin (e.g. red pepper), subjects using anorectic or related compounds (sympathomimetic compounds), athletes or regularly active individuals (>30 min of intense physical activity three times weekly) and subjects with a caffeine intake >200 mg/d (about two small cups of coffee daily) were all excluded from the study. In addition, all fourteen participants had a stable weight (+/-3 kg) for at least 3 months before the protocol and no history of weight loss >/= 4.5 kg). Study Design The present study has a randomized, placebo-controlled, double-blind, cross-over design. Subjects spent 24 h in a metabolic chamber on five separate occasions and were randomly assigned to receive one of the following five treatments, three times daily: (1) Mixture of green tea and Guarana extracts: 200 mg caffeine (600 mg/d) fl 90 mg EGCG (270 mg/d); (2) Mixture of green tea and Guarana extracts: 200 mg caffeine (600 mg/d) fl 200 mg EGCG (600 mg/d); (3) Mixture of green tea and Guarana extracts: 200 mg caffeine (600 mg/d) fl 300 mg EGCG (900 mg/d); (4) Mixture of green tea and Guarana extracts: 200 mg caffeine (600 mg/d) fl 400 mg EGCG (1200 mg/d); (5) Placebo: inert filler of cellulose. The capsules of the four pre-existing mixtures and placebo were developed and standardized by Iovate Health Sciences Research Inc. (previously known as Muscle Tech Research and Development; Mississauga, Ontario, Canada). The four mixtures contained a green tea extract in which EGCG represented 45% dry weight. Therefore, these mixtures also contained unknown amounts of other catechins and possibly caffeine. The mixtures were also composed of a Guarana extract that contained caffeine and other possibly unknown components. The amounts of green tea and Guarana extracts were adjusted to obtain the desired dose of EGCG (90, 200, 300 and 400 mg/mixture) and caffeine (fixed dose of 200 mg for each mixture). Subjects received all of the treatments but in a different order depending on the randomization to which they were assigned. The first dose was given at 08.00 hours, followed by the standardized breakfast 30 min later. The second dose was at 12.00 hours, followed by a standardized lunch 30 min later. The third dose was at 18.00 hours, followed by a standardized dinner 30 min later. At each metabolic chamber visit, the 24 h ambulatory blood pressure monitor was installed. The 24 h urine collection was also performed at these visits. It is to be noted that subjects did not change their diet or activity pattern during the study. The various sessions in the metabolic chamber were administered within an interval of 5–10 d of each other for each subject. Measurements Twenty-four Hour Blood Pressure and Heart Rate Monitoring. To determine the 24 h means (overnight + daily) for systolic and diastolic blood pressure and heart rate, subjects were asked to wear an ambulatory blood pressure monitor in the metabolic chamber. The ambulatory blood pressure device (model #90 207; Space Labs Medical, Redmond, WA, USA) consists of a programmed console that is worn on the belt with an appropriate size cuff (depending on arm circumference) worn on the non-dominant arm and a cable connecting the console to the cuff. Data were recorded at frequent intervals throughout the day (every 30 min from 08.00 to 22.00 hours) and at night (every hour from 22.00 to 08.00 hours) and were then analysed with a computerized system (FT1000A). Twenty-four Hour Urine Collection (urinary nitrogen and catecholamine excretion). While in the metabolic chamber (five visits), patients were asked to collect urine for a 24 h period and a sample was taken for analysis to measure catecholamine excretion. The extraction and separation of urinary catecholamines was done using C18 solid-phase extraction sorbent and HPLC (Talwar et al. 2002). Statistical analysis JUMP Software 3.1.6.2 (SAS Institute Inc., Cary, NC, USA) was used for all analyses. ANOVA for repeated measures was performed to determine if there were differences between the effects of the five treatments on heart rate, systolic and diastolic blood pressure (24 h, day and night), and noradrenaline and adrenaline excretion. When ANOVA was significant (P,0·05), paired t tests were performed to compare each pair of treatments in order to detect the treatments between which there were the differences. As there were multiple comparisons, Bonferonni correction was applied and results of the paired t tests were considered statistically significant at P<0.005 (ten comparisons).
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How many outcome-specific endpoints are evaluated? 3
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Blood pressure (SBP and DBP)
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List additional health endpoints (separately). 2 Heart rate
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List additional health endpoints (separately).3 Urine catecholamines
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List additional health endpoints (separately).4
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List additional health endpoints (separately).5
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List additional health endpoints (separately).6
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Clinical, physiological, other Physiological
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What is the study design? Controlled Trial
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Randomized or Non-Randomized? RCT
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What were the diagnostics or methods used to measure the outcome? Objective
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Optional: Name of Method or short description 24 h means (overnight + daily) for systolic and diastolic blood pressure and heart rate were measured using an ambulatory blood pressure device (model #90 207; Space Labs Medical, Redmond, WA, USA). The extraction and separation of urinary catecholamines was done using C18 solid-phase extraction sorbent and HPLC (Talwar et al. 2002).
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Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other? other
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Measured or self reported? Measured
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Children, adolescents, adults, or pregnant included? Adults
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Subjects served as their own controls
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) None
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What conflicts of interest were reported? No information provided
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Refid 16176615
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What were the sources of funding? This research was supported by Iovate Health Sciences Research Inc. A. T. is partly supported by the Canada Research Chair in Physical Activity, Nutrition and Energy Balance.
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Results & Comparisons

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